Evaluation Of The Active Constituents In Ginkgo Biloba And Its Mechanism For The Treatment Of Airway Inflammation

The last two decades has seen an increase in the worldwide prevalence of respiratory diseases,such as chronic obstructive pulmonary disease?COPD?,asthma,and pulmonary fibrosis.However,most drugs such as corticosteroids cause unpleasant side effects.As yet disease and symptom is lighter,taking a certain curative effect and safe without side effects of resource,will be an effective way of prevention and treatment of airway inflammation.Ginkgo biloba has long been used in ancient China for the treatment of cough,asthma,and other lung diseases.It's recorded in Chinese pharmacopoeia as well as in the herbal book Pen Ts'ao Kang Mu.Numerous studies were focused on the functions of cardiovascular disease,whereas only a few studies have focused on airway inflammation.On the other hand,limited research has investigated the active compounds in Ginkgo leaves for the treatment of airway inflammation.This study mainly explored the active substances in Ginkgo biloba for the treatment of airway diseases and elucidated its mechanism of action.In our paper,the biological effects of different G.biloba extracts were evaluated in an ovalbumin-induced allergic mouse model.Anti-inflammatory compounds were analysed by HPLC-MS and evaluated by docking calculations.Finally,the anti-inflammatory properties of the active constituents were evaluated on cell and animal models and the preparation process was studied in detail,the main results are as follows:?1?The therapeutic effects of different G.biloba extracts?full extract of Ginkgo biloba seed,full extract of Ginkgo biloba leaf,the extract of total flavonol glycosides,the extract of terpene trilactones,ethyl acetate extract of G.biloba?in an OVA-induced allergic animal model were evaluated.Our data clearly indicated that,compared with other groups,ethyl acetate extract treatment significantly reduced the production of OVA-specific cytokines in OVA-sensitised mice.?2?The results of HPLC-MS analysis indicated that four biflavones,namely,bilobetin,ginkgetin,isoginkgetin,and sciadopitysin,were the main compounds in the ethyl acetate extract of G.biloba.Animal experiments showed that the anti-airway inflammation activity of ethyl acetate extract of Ginkgo biloba decreased significantly after the removal of Ginkgo biloba biflavonoids,indicating that the main anti-airway inflammation active components in ethyl acetate extract was Ginkgo biloba biflavonoids.Leukocyte elastase showed a high fit score with four biflavones using the PharmMapper server.Our docking calculations were performed via AutoDock 4.2.The lowest binding free energy of ginkgetin was-6.69 kcal/mol and sivelestat was-5.36 kcal/mol,suggesting biflavones might be an effective HNE inhibitor.The bio-activity of biflavones was evaluated in vitro:the reaction for HNE inhibition assay was tested using a fluorescence spectrometer and a circular dichroism.From the result of HNE inhibition assay,ginkgetin shows a high inhibitory activity(IC₅₀=40.8 nmol/L).The secondary protein conformation of HNE was found to show an?-helix decrease and a?-sheet increase.These results demonstrated that biflavones might effectively inhibit the activity of HNE.?3?Mechanism of Ginkgo biloba biflavonoids for the treatment of airway inflammation was valued by cell and animal model:biflavones decrease the mRNA expression of MUC5AC in A549 cells.Biflavones could markedly suppress the abnormal expression of the Akt and p38 pathways and then influenced the expression of IL-8 mRNA in A549 cells.The effect of the four biflavones on the OVA-induced allergy animal model was valuable.Dose-dependent decreases in the expression of MUC5AC mRNA,IL-8production and the prodution of MUC5AC were observed in the biflavone-treated groups.In conclusion,biflavonoids could inhibit the activity of leukocyte elastase,and then reduce the secretion of airway mucin and the inflammatory factor IL-8,influence the infiltration of inflammatory cells in the lung.?4?An experiment has been designed to evaluated the hepatic and renal toxic potential of ethyl acetate extract of G.biloba with a dosage of 50mg/kg·bw;500mg/kg·bw;2000mg/kg·bw.The results showed low toxicity of the after acute oral exposure.According to the data,there was no relevant toxicity and LD₅₀ was established as above2000mg/kg body weight.?5?The extraction technology of standard Ginkgo biloba extract?EGB761?was studied.It was found that the biflavonoids were completely eliminated in EGB761,which also explained that the ancient books of Chinese medicine recorded that Ginkgo biloba had antitussive and antiasthmatic effects,while the modern literature reported less.Therefore,the author developed a new production technology of Ginkgo biloba resources.This technology does not change the original standard extraction process of Ginkgo biloba extract?EGB761?,but also can obtain high content of Ginkgo biloba biflavonoids extract.The total content of four biflavonoids was 87.31%,and the yield of total biflavonoids was56.92%.In this paper,the active constituents of Ginkgo biloba against airway inflammation and the mechanisms were studied,then the extraction process was developed,which provided an important basis for the development of functional food and medicine.